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        검색결과 60

        21.
        2017.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study investigates the main growth mechanism of InP during InP/ZnS reaction of quantum dots (QDs). The size of the InP core, considering a synthesis time of 1-30 min, increased from the initial 2.56 nm to 3.97 nm. As a result of applying the proposed particle growth model, the migration mechanism, with time index 7, was found to be the main reaction. In addition, after the removal of unreacted In and P precursors from bath, further InP growth (of up to 4.19 nm (5%)), was observed when ZnS was added. The full width at half maximum (FWHM) of the synthesized InP/ZnS quantum dots was found to be relatively uniform, measuring about 59 nm. However, kinetic growth mechanism provides limited information for InP / ZnS core shell QDs, because the surface state of InP changes with reaction time. Further study is necessary, in order to clearly determine the kinetic growth mechanism of InP / ZnS core shell QDs.
        4,000원
        22.
        2017.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We have investigated the washing method of as-synthesized CdSe/ZnS core/shell structure quantum dots (QDs) and the effective surface passivation method of the washed QDs using PMMA. The quantum yield (QY%) of assynthesized QDs decreases with time, from 79.3% to 21.1%, owing to surface reaction with residual organics. The decreased QY% is restored to the QY% of as-synthesized QDs by washing. However, the QY% of washed QDs also decreases with time, owing to the absence of surface passivation layer. On the other hand, the PMMA-treated QDs maintained a relatively higher QY% after washing than that of the washed QDs that were kept in toluene solution for 30 days. Formation of the PMMA coating layer on CdSe/ZnS QD surface is confirmed by HR-TEM and FT-IR. It is found that the PMMA surface coating, when combined with washing, is useful to be applied in the storage of QDs, owing to its long-term stability.
        4,000원
        23.
        2016.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 칼슘과 철 그리고 철과 아연의 상호작용과 신뢰성있는 영양정보를 제공하기 위해 영양강조표시제품중 칼슘, 철, 아연의 함량을 분석하고 표시량과 분석값을 비교하였다. 칼슘, 철, 아연을 강조표시한 제품(시리얼, 과자, 두유, 초콜릿가공품, 기타코코아가공품, 당류가공품, 과줆채음료, 고형차) 총 42건을 수거하였으며 칼슘, 철, 아연은 무기성분의 건식분해법으로 전 처리한 후 Inductively Coupled Plasma Spectrometer (ICP)로 실험하였다. 칼슘이 강조표시된 제품 42건에 대한 표시량 비율은 87~176%이 었으며, 철이 강조표시된 제품 13건에 대한 표시량 비율은 84~167%, 아연이 강조표시된 제품 6건에 대한 표시량비율은 98~275%였다. 모든 분석값이 표시량 대비 80% 이상으로 식품 등의 표시기준을 충족하였다. 칼슘과 철의 상호작용은 한국인의 칼슘 섭취가 1일 권장량의 68.7% 수준으로 부족하므로 칼슘의 과다섭취로 인한 철의 흡수방해는 우려할 만한 상황은 아닌 것으로 보인다. 또한, 분석한 영양강조표시제품의 철과 아연의 함량 비율이 1.53:1이 최대였으므로 철의 과다섭취로 인한 아연의 흡수방해는 우려할 만한 상황은 아니었다. 그러나 업체에서는 칼슘, 철, 아연을 강조한제품을 생산할 시에 영양소의 상호작용을 고려하여 생산을 해야 할 것이고 소비자에게 정확한 영양정보를 제공하고 적정량의 영양섭취를 위해서는 지속적인 모니터링을 통해 식품표시에 대한 주기적인 관리가 필요할 것으로 생각된다.
        4,000원
        24.
        2016.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Quantum dots (QDs) are capable of controlling the typical emission and absorption wavelengths because of the bandgap widening effect of nanometer-sized particles. These phosphor particles have been used in optical devices, photovoltaic devices, advanced display devices, and several biomedical complexes. In this study, we synthesize ZnSe QDs with controlled surface defects by a heating-up method. The optical properties of the synthesized particles are analyzed using UV-visible and photoluminescence (PL) measurements. Calculations indicate nearly monodisperse particles with a size of about 5.1 nm at 260℃ (full width at half maximum = 27.7 nm). Furthermore, the study results confirm that successful doping is achieved by adding Eu3+ preparing the growth phase of the ZnSe:Eu QDs when heating-up method. Further, we investigate the correlation between the surface defects and the luminescent properties of the QDs.
        4,000원
        25.
        2016.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        High-quality colloidal CdSe/ZnS (core/shell) is synthesized using a continuous microreactor. The particle size of the synthesized quantum dots (QDs) is a function of the precursor flow rate; as the precursor flow rate increases, the size of the QDs decreases and the band gap energy increases. The photoluminescence properties are found to depend strongly on the flow rate of the CdSe precursor owing to the change in the core size. In addition, a gradual shift in the maximum luminescent wave (λmax) to shorter wavelengths (blue shift) is found owing to the decrease in the QD size in accordance with the quantum confinement effect. The ZnS shell decreases the surface defect concentration of CdSe. It also lowers the thermal energy dissipation by increasing the concentration of recombination. Thus, a relatively high emission and quantum yield occur because of an increase in the optical energy emitted at equal concentration. In addition, the maximum quantum yield is derived for process conditions of 0.35 ml/min and is related to the optimum thickness of the shell material.
        3,000원
        26.
        2016.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, to improve the in vitro development of various cells including cloned embryos, the effects that isoproterenol and melatonin have on in vitro development of porcine parthenogenetic oocytes were investigated. Parthenogenetic activation was induced with electrical stimulation, BSA and 6-DMAP treatment. 10-7 M of melatonin and isoproterenol (10-10, 10-12 and 10-14 M) were supplemented for in vitro maturation (IVM) and in vitro culture (IVC) medium, with different concentrations. When isoproterenol and melatonin were supplemented in IVM medium with different concentrations, there was no significant (P<0.05) difference of maturation rate in the treatment groups as well as in that of only melatonin. As isoproterenol and melatonin were supplemented in IVM medium with different concentrations, blastocyst rates of isoproterenol 10-12 M treatment group (37.1%) were significantly (P<0.05) higher than control group (26.0%). Isoproterenol and melatonin were supplemented in IVC medium with different concentrations, then the cleavage rate of 10-12 M isoproterenol treatment group (82.2%) was significantly (P<0.05) higher than the group that melatonin was only supplemented (70.9%). There was no difference of blastocyst rate between the treatment groups. When isoproterenol and melatonin were supplemented for IVM+IVC medium with different concentrations, the cleavage rate of 10-12 M isoproterenol treatment group (92.5%) was significantly (P<0.05) higher than the control group (82.8%) and the group that melatonin was only treated (81.6%). The blastocyst rate of 10-12 M as 45.6% was significantly (P<0.05) higher than control group (25.2%) and melatonin treatment group (31.2%). The cell number of blastocyst in 10-12 M isoproterenol treatment group 35.5±3.4 was significantly (P<0.05) highest. The results of this study showed that the development rate of IVC when both isoproterenol and melatonin were supplemented was higher than when melatonin was only supplemented. Therefore, it is concluded that isoproterenol is rather effective in the activation of melatonin. 10-7 M melatonin and 10-12 M isoproterenol were considered suitable concentration.
        4,000원
        27.
        2015.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study was to evaluate the sodium-related dietary attitudes, behaviors, and nutritional knowledge in university students according to the practice of dietary guidelines for Koreans established by the Ministry of Health and Welfare, Republic of Korea. Based on the total practice score related to the dietary guidelines (PDG), we classified subjects into a “low practice of the dietary guidelines (LPDG)” group (n=94, male=43, female=51) (total score of PDG ≤13) and a “high practice of the dietary guidelines (HPDG)” group (n=56, male=32, female=24) (total score of PDG >13). Subjects were asked about general characteristics, lifestyle, salt-related dietary attitudes, behaviors, and nutritional knowledge using a questionnaire. The LPDG group had more subjects who were breakfast skippers (p<0.001) compared to the HPDG group. The LPDG group (31.26) had a significantly lower score in terms of salt-related dietary attitudes compared to the HPDG group (33.77) (p=0.0042). The score for salt-related dietary attitudes was significantly higher in the HPDG (32.52) group than in the LPDG (29.91) group (p=0.0041). There was no significant difference in the total score for salt-related nutrition knowledge between the groups. The correlation analysis indicated that the dietary guidelines practice score had a positive correlation with the salt-related dietary attitude score (r=0.3593, p<0.0001) and the dietary attitude score (r=0.3443, p<0.0001) after adjustments for sex. These results show that the degree of adherence to the dietary guidelines for adults may be related to sodium-related dietary attitudes, behaviors, and nutrition knowledge.
        4,200원
        28.
        2015.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The monolayer engineering diamond particles are aligned on the oxygen free Cu plates with electroless Ni plating layer. The mean diamond particle sizes of 15, 23 and 50 μm are used as thermal conductivity pathway for fabricating metal/carbon multi-layer composite material systems. Interconnected void structure of irregular shaped diamond particles allow dense electroless Ni plating layer on Cu plate and fixing them with 37-43% Ni thickness of their mean diameter. The thermal conductivity decrease with increasing measurement temperature up to 150oC in all diamond size conditions. When the diamond particle size is increased from 15 μm to 50 μm (Max. 304 W/mK at room temperature) tended to increase thermal conductivity, because the volume fraction of diamond is increased inside plating layer.
        3,000원
        31.
        2014.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 장애인 돕기 캠페인에 대한 반응에 공감적 관심과 소구 유형(이성적/감성적)이 미치는 영향을 살펴 보았다. 공감적 관심은 이타적 동기를 활성화하는 감성적 개인 성향을 지칭한다. 실험은 2단계로 구성하였는데, 1단계에서는 피험자들의 공감적 관심의 정도를 측정하고 2단계에서는 이성적 소구와 감성적 소구로 차별화된 캠 페인을 보여주었다. 이에 따라 전체 실험은 공감적 관심(2) ✕ 이성적/감성적 유형(2)으로 설계되었다. 그 결과, 돕기 태도와 행위 의도의 측정에서 공감적 관심과 소구 유형의 상호작용이 도출되었다. 이성적 소구에서 공감적 관심이 높은 개인들이 낮은 개인들에 비하여 상대적으로 호의적인 반응을 보여주었다. 감성적 소구에서는 공감 적 관심이 높고 낮음에 따라 차이가 없었다. 이 결과로부터 이타적 성향인 공감적 관심이 높은 개인들에게 이성 적 소구가 더 유용하다는 해석이 가능하여, 감성적 소구의 중요성을 강조해온 과거 돕기 캠페인 연구의 내용과 차별화된다.
        4,000원
        37.
        2012.11 구독 인증기관 무료, 개인회원 유료
        한국 남해동부해역에서 해양쓰레기의 이동을 파악하고자 수치모델(POM)을 실시하였다. 연구해역의 대·소조기 창조시에의 조류는 서향류 성분이 우세하였고,낙조시에는 동향류의 성분이 우세하였다. 동계의 잔차류는 표·중·저층에서 대마도의 동수도와 서수도를 따라 동북향 하는 흐름이 우세하였으며, 이와 같은 현상은 쓰시마 난류와 유사한 흐름을 나타냈다. 또한 이 지역은 수심의 영향을 받아 대마도의 서쪽과 북서쪽 및 북쪽에 와류가 형성되었다.
        3,000원
        39.
        2012.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was investigated the effects of marinating beef with thirteen different commercial vinegars on quality traits of Biceps femoris (BF) muscle of Hanwoo. Samples were divided into thirteen portions and injected with vinegar which was equivalent to 10% of the sample weight. The samples were all marinated for 15 hrs at 4℃ for experiments. The pH and cooking loss were tended to decrease (p<0.05) on all the vinegars and swollen rate was increased only on pomegranate vinegar. Shear force was decreased on all the thirteen commercial vinegars except persimmon vinegar. Most of commercial vinegars had influenced on water holding capacity, excluding omija-persimmon, pomegranate and grape vinegars. The yield was the greatest with the aloe-apple (p<0.05). Redness (a) was stable on aloe-apple and omija-persimmon vinegars. With an improvement of experimental design and process for future work, the results could be suggested to industrial utilization wherein low-quality meat could be improved by simple marination.
        4,000원
        40.
        2012.06 구독 인증기관·개인회원 무료
        돼지 핵이식 복제수정란의 체외 발달율을 개선하고자, 핵이 주입된 수핵난자를 전기자극 에 의한 융합 후 demecolcine으로 세포질 활성화 처리를 실시하였다. 2-세포기로 분할 전 까지 핵의 이상분열을 억제하여 정상적인 핵형 유지여부 및 demecolcine이 핵의 방출을 유 도하여 탈핵의 전 처리, 핵이식 후 활성화의 후 처리 및 탈핵 전․후 처리를 모두 한 핵이 식 수정란의 체외발달율을 조사하였다. 융합이 이루어진 복제 수정란에 demecolcine을 4시간 처리하였을 때 정상적인 핵 모양인 CLC(clustered chromosomes) 상태는 43.2%로서 무 처리구의 15.0%보다는 높았으며, 1PN (single pronucleus) 상태는 46.9%로서 대조구의 35.0%와는 차이가 없었다. 비정상적인 핵 형인 ≥2PN, PPB+CLC or PN 및 ≥2PN 7.4, 0 및 2.5%로서 무 처리구의 17.5, 22.5 및 10%로서 처리구가 낮았다. 융합 이후 16시간에는 1PN이 85.0%로서 대조구의 56.7%보다 는 높았다. 분할율은 전․후 모두 처리구에서 86.4±2%로서 후 처리(81.3±6%)와 대조구(79.6±6%) 보 다 높았으며, 전 처리의 85.7±2%와는 차이가 없었다. 배반포기로의 발달율에 있어서도 전․후 처리가 18.1±3%로서 전 처리(11.0±3%)와 대조구(11.3±1%)에 비하여 높았으나, 후 처리의 15.5±1%와는 차이가 없었다. 배반포기 수정란의 할구수도 전․후 처리가 21.6±6% 로서 전, 후 처리 및 대조구의 각각 18.8±8%, 19.4±3% 및 19.7±2%보다 많았다. Demecolcine을 돼지 복제 수정란에 처리하면 분할 전까지 핵의 이상 분열을 억제하는 것 이 확인되었으며, demecolcine 처리에 의한 탈핵은 수핵난자의 세포질 손상을 감소시키고 보다 용이하게 할 수 있다. 본 연구에서와 같이 탈핵 및 활성화를 목적으로 탈핵 전․후 처 리를 하였을 때 체외발달율이 다소 개선되는 경향을 보였다.
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